1. Field of the Invention
The present invention relates to image processing of an LCD (liquid crystal display), and more particularly, to a compressive overdrive circuit and associated method.
2. Description of the Prior Art
An LCD has the advantages of being a small size and light-weight, therefore, LCDs are gradually substituting for conventional cathode ray tube displays. In addition, as the frequency of display drive signals increases, liquid crystal molecules can not quickly rotate to a desired specific angle with changes in the drive signal. The image blur problem is serious when a difference of the pixel values between continuous frames is large.
FIG. 1 shows a prior art overdrive circuit 10. Each pixel, RN, GN, and BN respectively represents the pixel values of a current frame FN in the R/G/B color domain. RN-1, GN-1, and BN-1 respectively represent the pixel values of a previous frame FN-1 in the R/G/B color domain. The overdrive circuit 10 utilizes a look-up table (LUT) to output color signals ROUT, GOUT, and BOUT to compensate rotating speed of the liquid crystal molecules, so as to improve display quality.
However, the prior art stores all pixel values of the previous frame for overdrive. As LCD resolution increases, more DRAM is required for overdrive processing and thus cost increases.